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MongoDB Compute Resource Autoscaling

This guide will give an overview on how KubeDB Autoscaler operator autoscales the database compute resources i.e. cpu and memory using mongodbautoscaler crd.

Before You Begin

• You should be familiar with the following KubeDB concepts:
  • MongoDB
  • MongoDBAutoscaler
  • MongoDBOpsRequest

How Compute Autoscaling Works

The following diagram shows how KubeDB Autoscaler operator autoscales the resources of MongoDB database components. Open the image in a new tab to see the enlarged version.

  

The Auto Scaling process consists of the following steps:

1. At first, a user creates a MongoDB Custom Resource Object (CRO).

2. KubeDB Provisioner operator watches the MongoDB CRO.

3. When the operator finds a MongoDB CRO, it creates required number of StatefulSets and related necessary stuff like secrets, services, etc.

4. Then, in order to set up autoscaling of the various components (ie. ReplicaSet, Shard, ConfigServer, Mongos, etc.) of the MongoDB database the user creates a MongoDBAutoscaler CRO with desired configuration.

5. KubeDB Autoscaler operator watches the MongoDBAutoscaler CRO.

6. KubeDB Autoscaler operator generates recommendation using the modified version of kubernetes official recommender for different components of the database, as specified in the MongoDBAutoscaler CRO.

7. If the generated recommendation doesn’t match the current resources of the database, then KubeDB Autoscaler operator creates a MongoDBOpsRequest CRO to scale the database to match the recommendation generated.

8. KubeDB Ops-manager operator watches the MongoDBOpsRequest CRO.

9. Then the KubeDB Ops-manager operator will scale the database component vertically as specified on the MongoDBOpsRequest CRO.

In the next docs, we are going to show a step by step guide on Autoscaling of various MongoDB database components using MongoDBAutoscaler CRD.